The scientific tourist #183 — rock flour in the Tracy Arm fjord

A quick shot of a bit of calved glacier from Alaska’s Tracy Arm fjord:

The charcoal gray stuff is rock flour, the remains of rock that’s been pulverized to the consistency of a fine powder by the grinding action of glacial erosion. Normally you only see it in streams, being carried away from a glacier in meltwater. In this case, a calved chunk of a glacier brought some rock flour out in a more-or-less dry form for handy inspection from our cruise ship.